This invention relates to slant axis rotary mechanisms used as engines, pumps, compressors or the like. More specifically, it relates to improvements in the fabrication of rotors in such mechanisms.
As is well known, slant axis rotary mechanisms include an angularly offset portion in their main shaft for journalling the rotor employed. Typically, a peripheral thrust collar will be disposed on the angularly offset portion. The presence of the thrust collar requires that either the shaft or the rotor be formed of two elements which are united during assembly such that the rotor sandwiches the thrust collar.
Ordinarily, the stresses encountered in the shaft are sufficiently high that it is made in one piece. Thus, the rotor is generally formed of two or more pieces. In state of the art constructions, one piece is threadably received by the other. The difficulty encountered with such a construction is the yielding of the screw threads which results in a loosening of the assembly and, in turn, causes portions of the rotor hub to rub against the housing. Moreover, it is difficult to machine the threads with the precision required. Relatively fine threads do not provide the requisite strength, while coarse threads present a great deal of friction during assembly so that it is difficult to unite the pieces with the desired degree of torque.